Stanisci Angela, Bricca Alessandro, Calabrese Valentina, Cutini Maurizio, Pauli Harald, Steinbauer Klaus, Carranza Maria Laura
EnvixLab, Department of Bioscience and Territory, University of Molise, Termoli, Italy.
Department of Science, University of RomaTre, Roma, Italy.
AoB Plants. 2020 Mar 26;12(2):plaa004. doi: 10.1093/aobpla/plaa004. eCollection 2020 Apr.
Mediterranean high mountain grasslands are shaped by climatic stress and understanding their functional adaptations can contribute to better understanding ecosystems' response to global change. The present work analyses the plant functional traits of high-elevation grasslands growing in Mediterranean limestone mountains to explore, at the community level, the presence of different plant strategies for resource use (conservative vs. acquisitive) and functional diversity syndromes (convergent or divergent). Thus, we compared the functional composition and diversity of the above-ground traits related to resource acquisition strategies of subalpine and alpine calcareous grasslands in the central Apennines, a mountain region characterized by a dry-summer Mediterranean climate. We used georeferenced vegetation plots and field-measured plant functional traits (plant maximum height, specific leaf area and leaf dry matter content) for the dominant species of two characteristic vegetation types: the subalpine community and the alpine community. Both communities are of particular conservation concern and are rich in endemic species for which plant functional traits are measured here for the first time. We analysed the functional composition and diversity using the community-weighted mean trait index and the functional diversity using Rao's function, and we assessed how much the observed pattern deviated from a random distribution by calculating the respective standardized effect sizes. The results highlighted that an acquisitive resource use strategy and relatively higher functional diversity of leaf traits prevail in the alpine community, optimizing a rapid carbon gain, which would help overcome the constraints exerted by the short growing season. The divergent functional strategy underlines the co-occurrence of different leaf traits in the alpine grasslands, which shows good adaptation to a microhabitat-rich environment. Conversely, in the subalpine grassland, a conservative resource use strategy and relatively lower functional diversity of the leaf traits are likely related to a high level resistance to aridity over a longer growing season. Our outcomes indicate the preadaptation strategy of the subalpine grassland to shift upwards to the alpine zone that will become warmer and drier as a result of anthropogenic climate change.
地中海高山草原受气候胁迫影响，了解其功能适应性有助于更好地理解生态系统对全球变化的响应。本研究分析了地中海石灰岩山区高海拔草原的植物功能性状，以在群落水平上探索不同植物资源利用策略（保守型与获取型）和功能多样性综合征（趋同或趋异）的存在情况。因此，我们比较了亚平宁山脉中部亚高山和高山钙质草原地上部分与资源获取策略相关的功能组成和多样性，该山区具有夏季干燥的地中海气候特征。我们使用了地理参考植被样地以及实地测量的两种典型植被类型（亚高山群落和高山群落）优势物种的植物功能性状（植物最大高度、比叶面积和叶片干物质含量）。这两个群落都受到特别的保护关注，并且富含特有物种，此处首次测量了这些物种的植物功能性状。我们使用群落加权平均性状指数分析功能组成和多样性，使用Rao函数分析功能多样性，并通过计算各自的标准化效应大小来评估观察到的模式与随机分布的偏离程度。结果表明，高山群落中普遍存在获取型资源利用策略和相对较高的叶片性状功能多样性，这有利于快速的碳积累，有助于克服生长季短所带来的限制。趋异的功能策略突出了高山草原中不同叶片性状的共存，这表明其对微生境丰富的环境具有良好的适应性。相反，在亚高山草原中，保守型资源利用策略和相对较低的叶片性状功能多样性可能与在较长生长季中对干旱的高度抗性有关。我们的研究结果表明，亚高山草原存在预先适应策略，可向上迁移至高山地带，而由于人为气候变化，该地带将变得更加温暖干燥。
